/**
 * 2009-9-9
 */
package cn.blu10ph.tools;

import java.io.*;
import java.util.zip.*;

/**
 * ZLib压缩工具
 *
 * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
public abstract class ZLibUtils {

    /**
     * 压缩
     *
     * @param data
     *            待压缩数据
     * @return byte[] 压缩后的数据
     */
    public static byte[] compress(byte[] data) {
        byte[] output = new byte[0];

        Deflater compresser = new Deflater();

        compresser.reset();
        compresser.setInput(data);
        compresser.finish();
        ByteArrayOutputStream bos = new ByteArrayOutputStream(data.length);
        try {
            byte[] buf = new byte[1024];
            while (!compresser.finished()) {
                int i = compresser.deflate(buf);
                bos.write(buf, 0, i);
            }
            output = bos.toByteArray();
        } catch (Exception e) {
            output = data;
            e.printStackTrace();
        } finally {
            try {
                bos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        compresser.end();
        return output;
    }

    /**
     * 压缩
     *
     * @param data
     *            待压缩数据
     *
     * @param os
     *            输出流
     */
    public static void compress(byte[] data, OutputStream os) {
        DeflaterOutputStream dos = new DeflaterOutputStream(os);

        try {
            dos.write(data, 0, data.length);

            dos.finish();

            dos.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 解压缩
     *
     * @param data
     *            待压缩的数据
     * @return byte[] 解压缩后的数据
     */
    public static byte[] decompress(byte[] data) {
        byte[] output = new byte[0];

        Inflater decompresser = new Inflater();
        decompresser.reset();
        decompresser.setInput(data);

        ByteArrayOutputStream o = new ByteArrayOutputStream(data.length);
        try {
            byte[] buf = new byte[1024];
            while (!decompresser.finished()) {
                int i = decompresser.inflate(buf);
                o.write(buf, 0, i);
            }
            output = o.toByteArray();
        } catch (Exception e) {
            output = data;
            e.printStackTrace();
        } finally {
            try {
                o.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        decompresser.end();
        return output;
    }

    /**
     * 解压缩
     *
     * @param is
     *            输入流
     * @return byte[] 解压缩后的数据
     */
    public static byte[] decompress(InputStream is) {
        InflaterInputStream iis = new InflaterInputStream(is);
        ByteArrayOutputStream o = new ByteArrayOutputStream(1024);
        try {
            int i = 1024;
            byte[] buf = new byte[i];

            while ((i = iis.read(buf, 0, i)) > 0) {
                o.write(buf, 0, i);
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
        return o.toByteArray();
    }

    public static Boolean decompress(InputStream is,FileOutputStream os) {
        Boolean flg = false;
        InflaterInputStream iis = new InflaterInputStream(is);
        try {
            int i = 1024*1024*4;
            byte[] buf = new byte[i];
            int head;
            StringBuffer objectType = new StringBuffer();								//GitObject类型(commit/tree/blob)

            int offset = 0;
            int spaceNum = 0;
            while ((spaceNum<2) && (head=iis.read())!=-1) {
                if(0==head || 32==head){
                    spaceNum++;
                }
                if(spaceNum==0){													//如果还没遇到分割符
                    objectType.append((char)head);									//字符加入GitObject类型
                }
                offset++;
            }
//            System.out.println("type:"+objectType.toString());
            if(!objectType.toString().equals("blob")){
                return flg;
            }

//            System.out.println("偏移:"+offset);

            while ((i = iis.read(buf, 0, i)) > 0) {
                os.write(buf, 0, i);
            }
            os.flush();

            flg = true;
        } catch (Exception e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
        return flg;
    }
}